1. Field of the Invention
The present invention relates to a silver halide color photographic light-sensitive material, and more particularly to a silver halide color photographic light-sensitive material that is improved on the color developability as well as on the developed image sharpness.
2. Description of the Prior Art
After an imagewise exposure of a silver halide color photographic light-sensitive material, the light-sensitive material is developed by an aromatic primary amine-type developing agent in the presence of a coupler capable of forming a dye by the reaction thereof with the aromatic primary amine-type developing agent, then bleached, and then fixed, whereby a dye image can be formed.
Generally speaking, for the above dye image formation, a negative-positive method is used in which a dye image (negative image) having complementary color relation with a subject is once formed on a negative light-sensitive material, and the negative image is then projected upon a color photographic printing paper to reproduce thereon a dye image (positive image) corresponding to the subject, the dye image having complementary color relation with the negative image.
In recent years, there has been a tendency toward making cameras more compact as well as making a light-sensitive material's processing period shorter. This tendency has now increasingly given rise to the need for producing smaller-size image-photographic (smaller-format) negative-type color photographic light-sensitive materials. The smaller the size of a negative image the larger the increase in the magnification used when projecting the image upon a color photographic printing paper. If a negative is of a graininess that cannot cover the increase in the magnification, the graininess and sharpness produce an image of poor quality, which become a large problem. Many attempts have been and are now being made to improve the graininess and sharpness.
The sharpness can be improved largely by reducing the thickness of the emulsion layer. In order to reduce the thickness, it is necessary to reduce as much as possible the gelatin content of the emulsion layer. However, if the gelatin content is reduced and a high-boiling organic solvent is used as a coupler solvent, a phenomenon called "sweating" tends to occur which is undesirable for the characteristics of the light-sensitive material. The "sweating" is a phenomenon that an oily component oozes out on the surface of a light-sensitive material when the material is placed under a highly moist air condition. The sweating phenomenon can be prevented by the use of a polymer coupler that is obtained by the polymerization of a coupler monomer. That is, the incorporation of a polymer coupler into the emulsion layer enables to prevent the sweatng phenomenon even when the gelatin content of the emulsion layer is reduced, thus accomplishing the thinning of the emulsion layer.
Regarding the polymer coupler, U.S. Pat. Nos. 3,370,952 and 4,080,211 describe methods for producing it by the emulsion polymerization of a monomer coupler; and U.S. Pat. No. 3,451,820 describes a method for dispersing an oleophilic polymer coupler obtained by polymerizing a monomer coupler in the oil droplet from into an aqueous gelatin solution.
Those for cyan polymer couplers are described in U.S. Pat. No. 3,767,412, Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) Nos. 161541/1981 and 161542/1981, and those for magenta polymer couplers in U.S. Pat. Nos. 3,623,871 and 4,123,281, and Japanese Patent O.P.I. Publication Nos. 94752/1982, 28745/1983 and 120252/1983.
However, these polymer couplers, although they have the above-mentioned excellent advantages, are disadvantageous in respect that their coupling reaction is so slow that no adequate developed-color density is obtained.
West German Pat. No. 2,725,591, U.S. Pat. No. 3,926,496, and Japanese Patent O.P.I. Publication No. 94752/1982 describe that the use of a two-equivalent magenta polymer coupler latex improves the coupling reactivity. However, the resulting formed color density is still not adequate.
Japanese Patent O.P.I. Publication No. 28745/1983 discloses the incorporation of a water-immiscible high-boiling organic solvent for the purpose of increasing the dispersing stability of a polymer coupler. However, the combined use of a high-boiling solvent known as an ordinary coupler solvent such as dibutyl phthalate, triphenyl-cresyl phosphate, etc., with a polymer coupler may improve slightly but cannot improve adequately the formed color density.